Large-Scale Evaluation of In Vitro Amphotericin B, Triazole, and Echinocandin Activity against Coccidioides Species from U.S. Institutions

Large-scale testing of Coccidioides isolates has not been performed, and the frequency of clinical isolates with elevated amphotericin B or triazole MICs has not been evaluated. Coccidioides isolates (n = 581) underwent antifungal susceptibility testing. Elevated MIC values were observed for fluconazole (≥16 μg/ml, 37.3% of isolates; ≥32 μg/ml, 7.9% of isolates), itraconazole (≥2 μg/ml, 1.0% of isolates), posaconazole (≥1 μg/ml, 1.0% of isolates), and voriconazole (≥2 μg/ml, 1.2% of isolates). However, mold-active triazoles exhibited low MICs for the majority of isolates tested. Additional correlation with patient outcomes to determine the relevance of elevated MICs in Coccidioides isolates is needed.